This invention relates to pressure or pressure difference measuring transducers in general and more particularly to a transducer which is more compact and less sensitive to changes in the environment.
A pressure or pressure difference transducer which includes a diaphragm clamping housing, in which a measuring diaphragm is clamped between two fixed capacitor plates; a pressure housing, in which the diaphragm clamping housing is held by means of a ring shaped support element which is elastic in the radial direction; and separating diaphragms which, in the event of an overload, rest against surfaces correspondingly shaped as formed beds is described in Siemens Publication "TELEPERM Measuring Transducer K", Order No. E 682/1023. In this transducer, the support element consists of a ring shaped diaphragm which is, on the one hand, tightly connected to the diaphragm clamping housing at its outer circumference and is clamped, on the other hand, in the pressure housing. In this manner, the diaphragm clamping housing is suspended floatingly in the pressure housing. This suspension has the advantage that the spring stiffness of the measuring diaphragm is not influenced by the static pressure of the measuring medium.
Therefore, measuring errors due to changes of the static pressure do not occur in this known measuring transducer. The floating suspension of the diaphragm clamping housing, in the known measuring transducer, results in the further advantage that, in the event of an overload, excessive strain cannot occur in the measuring diaphragm since the elastic support element is connected parallel to the measuring diaphragm; this support element substantially takes up the volume of liquid which is pressed out under the separating diaphragm concerned when the measuring transducer is heavily overloaded on one side. Null errors due to excessive stretching of the measuring diaphragm are therefore avoided in the known measuring transducer.
It is an object of the present invention to provide a pressure or pressure difference transducer which, while retaining the advantages of the known measuring transducer, is distinguished by a comparatively compact design and can be produced considerably lower cost.